6 October 2011
Type 1 Gaucher disease (pronounced go-SHAY) is a progressive, genetic disorder that causes many different symptoms. A person with Gaucher disease can't produce enough of an essential enzyme called glucocerebrosidase (pronounced GLOO-ko-SER-e-bro-sy-daze), which breaks down a fatty substance called glucocerebroside. Without this enzyme, the fatty substance is not broken down, but instead builds up in the cells. These swollen cells are called Gaucher cells.
Over time, as Gaucher cells build up in the bone marrow and organs, they cause increasing damage, possibly including bone pain, skeletal damage, enlarged liver and spleen, low red blood cell count, and low platelet count. However, if the disease is recognized early, treatment can begin, potentially preventing irreversible damage.
Type 1 Gaucher disease affects approximately 1 in 45,000-60,000 people in the general population. It is more common among Ashkenazi Jews, affecting 1 in 850. Signs and symptoms may appear at any age.
Inheriting Gaucher Disease
Every person’s body contains tens of thousands of genes that help guide growth and development. Genes determine traits such as eye color and height. We all inherit two copies of every gene, one from each parent.
One of these genes controls the production of the enzyme glucocerebrosidase. A person develops Type 1 Gaucher disease if he or she inherits two defective copies of this gene (one from each parent). If a person only inherits one defective copy, he or she will not develop Type 1 Gaucher disease, but is considered a “carrier.” A carrier can pass the defective gene to his or her children.
With each pregnancy, each carrier has a 50% chance of passing on the defective gene. If both parents are carriers, there is a 25% chance their child will inherit two defective copies and will develop Type 1 Gaucher disease.
The charts below show the different ways the Gaucher gene can pass from one generation to the next.
The Ashkenazi Connection
As noted above, Type 1 Gaucher disease affects 45,000-60,000 people in the general population, but 1 in 850 Ashkenazi Jews. Approximately 1 in every 15 people of Ashkenazi decent is a carrier of Type 1 Gaucher disease. Because of this, genetic counseling and/or carrier testing for Gaucher disease may be particularly appropriate for people of Ashkenazi descent to help them address the complex social and reproductive issues they may face.
Signs and Symptoms
The build-up of Gaucher cells in various organs (especially the liver and spleen) and in bone marrow (leading to many skeletal complications) results in the signs and symptoms of Gaucher disease. The disease’s bone-related symptoms can be particularly painful and debilitating, making it hard to move. Children and adolescents with Gaucher disease may experience a delay in growth and development.
1: Enlarged liver and/or spleen
Gaucher patients may have protruding abdomens, caused by the liver and/or spleen swelling because of accumulated Gaucher cells. The spleen can swell to 5-75 times its normal size, and the liver can swell to 1.25-2.5 times its normal size. These symptoms can have many other effects, including loss of appetite (because the enlarged organs press on the stomach, creating a full feeling), blood-related problems related to an overactive spleen, liver disease, and low self-esteem related to appearance.
2: Low blood platelet count
Platelets allow blood to clot. They are formed in bone marrow and released into the blood. The build-up of Gaucher cells in bone marrow may cause fewer blood platelets to be produced. In addition, an enlarged, overactive spleen (caused by accumulated Gaucher cells) may break down platelets faster than they are produced. As a result, Gaucher patients’ blood may not clot well, and they may experience excessive bruising, frequent nosebleeds, bleeding gums, and longer, heavier menstrual periods.
3: Low red blood cell count (anemia)
Red blood cells are responsible for carrying oxygen to all cells in the body. The spleen is responsible for breaking down these cells, but when it is enlarged as a result of accumulated Gaucher cells, it may become overactive and break down blood cells faster than they are produced. The resulting red blood cell deficiency is called anemia, and it causes people to feel tired because the body is not getting enough oxygen. While anemia is often responsible for fatigue and low stamina in Gaucher patients, these symptoms may also result from a higher-than-normal metabolism found in many people with Gaucher disease.
4: Low white blood cell count
White blood cells are responsible for helping fight infection when bacteria or viruses enter the body. The spleen is responsible for filtering these cells, but when it is enlarged as a result of accumulated Gaucher cells, it may become overactive and filter white blood cells faster than usual. The resulting white blood cell deficiency makes it harder for the body to fend off infection, so Gaucher patients may get sick more frequently than other people.
5: Bone crisis
Gaucher patients may experience severe bone pain, called “bone crisis,” because Gaucher cells in the bone marrow may prevent blood from circulating properly. The pain is intense, often accompanied by fever, and can last from a few hours to a few days or even weeks. Patients often remain bedridden during this time.
6: Bone tissue death
As Gaucher cells accumulate in bone marrow, they can restrict normal blood flow—sometimes to the point that bone tissue dies. This bone destruction causes severe pain and can lead to fractures and joint collapse. Broken bones caused by disease rather than by trauma (like a fall or accident) are called pathological fractures.
7: Bone thinning
Type 1 Gaucher disease causes reduced mass and density of bone tissue, resulting in thin and weakened bone that is more susceptible to fractures.
8: Pathological fracture
Pathological fractures are broken bones caused by disease rather than by trauma (such as impact from a fall or accident). The accumulation of Gaucher cells in bone marrow can weaken bones in various ways, making them susceptible to such fractures resulting simply from normal activity.
9: Erlenmeyer flask deformity
Gaucher disease causes abnormalities in the way bones develop, causing them to form irregular shapes. The most common among Gaucher patients is the Erlenmeyer flask deformity (so named because its shape resembles a type of laboratory flask), in which the ends of the bone (most commonly the femur and tibia leg bones) are flared and flattened rather than rounded.